1.Technical Field
The present invention relates to transistor devices, and, more particularly, to multigate transistor devices and systems, and methods of their fabrication and use.
2. Description of the Related Art
Throughout the evolution and advancement of computing devices, the reduction of their size and their power consumption in a way that maintains or improves a high processing capacity has long been a design goal. Planar field-effect transistor (FET) devices, which have been widely used in integrated circuits for the past several decades, were found to be increasingly inefficient on the nanometer scale. Reducing the size of the channel between the terminals of planar transistors to this scale leads to an inefficient leakage of current in the off-state of the transistor, resulting in an increase in power consumption in its idle state. Multigate field-effect transistors (MuGFET) have been developed to address this problem, as they incorporate several gates that surround the channel between a source and drain terminal of the transistor on a plurality of surfaces, thereby enabling the suppression of leakage current in the off-state.
There are several different types of multi-gate devices. FinFETs and Trigate devices are two examples. FinFET devices include a thin fin, which can be made of silicon, that provides the channel between a source and a drain. The fin can be overlaid with a plurality of gates, where the gates can be on opposing sides of the fin. Trigates are similar to FinFETs in that they also employ fins. However, in a Trigate device, two vertical gates respectively envelope separate fins and a single top gate is overlaid on the two vertical gates. The top gate usually extends across a plurality of transistor cells in Trigate devices.